From the factory, most Animals come with a compression relese on the cam. Until several years ago most after market cams did not have one, now you can order them with the CR. If someone buys an Animal that has been used for kart racing, theres a good chance that it may not have the CR. It will break your fingers if trying to pull start it

Theres a couple of topics on here already about engine swaps. The Briggs Animal seems to be the most popular and this is the way I went. Only thing is that you don't have a lighting coil on that motor. I rigged up a small 12v battery in the belly pan and also a battery tender to plug in after use. You will need to have a throttle cable made up and cut a section out of the bulkhead so the engine fits properly.
Just look on the 1st or 2nd page and I had some pics as well as a couple other guys.